Induction-motor.



"13; c. JACKSON. INDU GTION MOTOR. APPLICATION FILED MAILB, mqo. nsnnwnn' APR. 11. 1904.

sssss S-SHEET PATENTED'APR. 17, 1906.

PATENTED APR. 17.1906.

D. 0.. JACKSON; I INDUCTION MOTOR. APPLIGATION FILED 11.3.1906. E NEWBD A 2. S'HBBTS-SHBET 2.

' w ccc RI EYE DUGALI) C, JACKSON, OF CHICAGQ, ILLINOIS.

INDUCTIQN-MQTOR. i

- Specification 01"- Letters Patent.

Patented April 17, 1906.

npplicationfiledlliarch 8,1900. Eenewccl Aprilll, 1904. SeriirlNaZOZfl'lO. 5

T at whom, it may con/06mm a Be it lmown that I, DUeALnjC.v JAoKsoN, a citizen of the United Statesfresiduig at Chicago, in the county of Cook and State of Illi-' nois, have invented a'certain new and useful Improvement in Induction-Motors, of which the following is afull, clear, concise, and exact description, reference being had to the accompanying drawings,'forming a part of this specification.

My invention relates to induction-motors,

'and more particularly to the starting a1 'r'angements therefor, and has for its object the provision of an improved method for oprating machines of this class.

As is well known, starting arrangements are generally provided for single-phase "induction-inotors, the said starting arrangements consisting in some cases of splitting the phasejof the alternating current and introducing it into the field-winding of the motor, so. that the same may start as a polyphase induction-n1otor,'and in other cases of arranging the motor to start as a repulsionmotor, using a commutator such as is described in Patent No. 389,352. Arrangements are usually provided by means of which the starting devices may be removed after the motor is in operation. This introduces complications and difficulties into the operationof such machines and reduces the eff ciency thereof. Various other arrange-v 'ments have also been employed for effecting the same object well known to those skilled in the art.-

- It is the prime object of my present invention to provide upon the armature a Winding which operates as an ordinary closed-coil direct-current win-ding in some of its modifications, with 'a'given number of poles in the field; The winding is an ordinary Winding of either drum or ring fashion and connected .atintervals to a commutator, the brushes being preferably short-oircuited or electrically connected through a variable resistance. Such'a winding when placed in a field with the correct number of poles-will operate under the influence of the alternating field, as is well understood in the art.

coilswhich are necessary in order that the ary "mature o erate as a direct-current armature I lacet ereon short-circuiting strips suitinterzonnecting various coils which will a mature.

In addition to the ordinary interconnections between the in connection with the armature-field, whereby I am enabled to change the number of poles to whose influence the armatureis subjected, the change in the number. of poles serving to alter the character of the magnetic flux threading the armature, this change serving to bring the short-circuiting strips into service, interconnecting pointsof unlike potential, the armature thereby o )erating practically as if constructed of siiort circuited coils and following the laws of operation of ordinary induction-arinatures. After the motorhas been brought up to speed by the use of its commutator, as just described, the connections of the field-winding may be changed so as to. change the number of pairs of poles and the armature will continue to run as a short-circuited induction-motor an In this arrangement I ani enabled todo away with all extraneous adjustment for splitting the phase of the alternating current, with its concomitant inconveniences and disadvantages, or changing of the con nections of the armature-coils, whereby irreg ularities and difficulties are introduced into the operation thereof, a simple means only being required for changing the number of poles acting upon the armature.

In the preferred embodiment of my invention I may employ the ordinary multiplepath direct-current armature-winding with cross-connected commutator. If this machine is constructed to operate with eight magnetic poles in the field, with the brushes electrically connected, the armature will operate on the repulsion principle described in Patent No. 389,3 '2, as is well understood. After the armature is running, if the connections of the field be then changed so as to give four magnetic oles, the armature will continue to run as a c osed-circuit armature in a single-phase induction-motor.

In place of the multiple-path winding with cross-connected commutator I may employ a series-path or progressive armatureewindr ing with shortrcircuiting strips disposed about the armature, .said short-circuiting strips being adapted to convey current between. conductors when the number of poles is changed for the running condition of the armature, in which case the armature may start on the repulsion principle with a lesser number of pales andu be operated at a greater number. i any of these arrangements the usual dis tributcd form of energizing-coils maybe em- .p Y v 1 will explain my invention more particularly with reference to the accompanying drawings,-in which I V Figure 1 is a diagrammatic'view of anarmature constructed in accordance with my invention, a multiple-path direct current Winding with cross.- connected commutator being shown thereonf'toget'her .with means for changing the number of magnetic poles to which the armature is subjected. Fig. 2 is a" view of. another embodiment of my invention as adapted to a' progressive ring-winding. Fig. '3 is a' similar view, but applied to adriim-winding.

, Like characters of reference. indicate like parts throughout the views. In Fig 1 I haveshoWn a source of current 1 supplying current to the distributed Winding ofthe field-ring 2. A switch 3 is employcfl for changing the interconnectionsv of the field coils, ,whereby the current may-be reversed intwo'of the coils, the switch being. an "ordinary double-throw switch connecting thet'erminals 4 t with the terminals5 5'or 6 6, respectivel. By the number of,magnetic poles in the fieldcircuit may be changed from 'four'to two, and vice -versa. I have shown-also my improved armature7 provided with an ordinary multiple-path ring-winding 8, suitably connected to a; commutator 9, oppositesegments of. the said commutator being "cross-connectedby shoi't-circu'iting strips, the brushes being placed preferably ninety d e 'rees apart and electrically connected, prefer ably through a resistance. When. the machine is connected up with four'magnetic poles N N S S.

in the field, it will "start as an ordinary fourpole repulsion-motor. If new the number of polesbe changed to two, N/ S,'by the aid of the switching means 3, the shortcircuiting strips acrossthe-commutator-will serve to short-circuit coils of opposite polarity upon the armature-circumference, thereby caus- 5o ing the armature to operateas an ordinary short-circuitcd induction-motor winding. As

will be seen, no operation other than changing the switch-handle of 1 1e switching means 3 is necessary to change the motor from its starting condition to its running condition, so that no change in the armature-circuits or commutator connections need be made, thereby providing a means for advantageously and easily starting-single-phase motors.

In Fig: 2 I have shown a Gramnie ring provided with a progressive Winding adapted to operate in acoordance'with my invention. The ringis provided with coils 1010, which are connected in the ordinary fashion, as is well understood in they art, the interconnecthe aid of this switch tions being of such a character that the machme is adapted to operate as an alternatingcurrent machine with a direct-current wind- .ing, two magnetic poles being in the field. The coils are connected at intervals to a commutator 11-, brushes 1212 engaging'the said commutator, the said brushes being electrically connected, preferably through a variable resistance or reactance 13. If an alternating current-is now impressed upon the field-winding, so that two poles will be created in the field, the armature will start and operate according tow'ell-known laws. After the are mature has attained its normal speed the interconnections of the field windirigs are changed by the aid of the means hereinbefore described, so that'four magnetic poles will be created in the field instead of two. In

order to adapt the armature to operate as a closed-coil induction-motor armature winding with four magnetic poles in the field, I-

provide thereon the cross-connecting conductors or short-circuiting strips 14, which electrically connect points of different elec-,

trical polarity upon the armaturecoils. These short-circuiting conductors which connect points of practically like electrical potential when the armature is operating n a two-poleifieldserve to convey current across the armature between coils of. unlike potential when the armature ,is operating in a four-pole field, thereby allowing the motor to start as an ordinary alternating-current repulsion-motor with two magnetic poles in the field and coeper'ating in the operation of the same as an ordinary induction-motor when there are four magnetic poles in the Referring now to Fig. 3, I have shown'a drum-armature as provided With my improved winding, consisting, preferably, of coils 1O 10, suitably interconnected as in the ordinary progressive winding and at intervals connected to the commutator 11, brushes 12 .12, preferably electrically connected through a variable resistance or reactance, being againshown. The connections upon the rear of the armature are indicated by the outside triangular vlines. as is Well understood. The operation of this armature is the same as the operation of the ring-armature, the machine being adaptedto start as atwopole machine and operate as a four-pole machine, th'e short-circuiting conductors 14 again permitting the machine'to start as a repulsion-motor with two poles in the field and cooperating to normally operate the same as an induction-motor when the num-.

been changed to four.

ber of field-poles has The special connections shown are generally equivalent to connectingadjacent commuta tor-segments together through satisfactory resistances unless the'relat'ive resistance of the special connections. and the regular com-L mutator connections are given a different ef- 1 1 feet by making the commutator connections of higher resistance; a

I have herein shown my invention as ap- ,plicd particularly to closed-coil direct-current armature-windings; but its application to other windings will be readily understood by those skilled in the art. I believe it to be r broadly new with me to use progressive ar- I mature windings adapted to operate in a field of a varying number of poles.

cise construction and arrangement as herein specifically set forth; but,

,Having thus described my invention, I

claim as new and desire to secure by Letters Patent the following:

1. The herein-described method of operat mg an induction-motor, provided with an armature having a progressive winding, a commutator, and auxiliary conductors for shortcircuiting conductors of the armature-winding, which consists in establishing a field by a single-phase alternating current, subjecting the progressive armature-winding to the inmlence of the said single-phase alternating field, inducing currentsin the said armature; winding and passing the same in progression through the coils of the armature-winding,

- motor.

the commutator and brushes, whereby the motor-is started, changing the number of poles-of the field to which the armature is subjected, and conveying current between the coils of the armature that are subject to unlike poles of the field through thesaid auxiliary conductors for normally operating said 2. The herein-described method of operat ing an induction-m otor provided with an armature having a progressive winding and having interconnections thereon for shortcircuiting coils thereof and a commutator, which consists in subjecting the same to a field having a plurality of magnetic poles, inducing currents in the said-armature-winding and passing the same through. the said armature-winding in progression, whereby the said motor is started, then subjecting the same to a field with a different number of magnetic pdles, inducing current-s in the said progressive armature winding and conveying the same through the said shortcircuiting con. ductors for normally operating said motors.

- 3. The herein-described method of operating an induction-motor provided with an armature having a progressive winding, a commutator and auxiliary conductors for electrically connecting difi'erent portions of the ing an induction-motor provided with anarmature having a progressive winding having interconnections thereon for short-cn'cuiting coils thereof and a commutator, which consists in establishing a field by a single-phase alternating current, subjecting the armature to the influence of said field so that portions of the armature electrically connected by means of the auxiliary conductors are normally under the influence of poles of like sign, conveying current through the said armature-conductors by way of the commutator and brushes for starting said motor, changing the number of poles of the field to which the armature subjected, and conveying current between the coils of the armature that are subject to unlike poles of the field through the said auxiliary conductors for normally operating said motor. v

5. The herein-described method of operating an induction-motor provided with an armature having a winding and auxiliary conductors for electrically connectingportions of the armature-windings, which consists in establishing a field by a single-phase alternating current, subjecting the armature thereto, and creating in the said armature at portions thereof which are electrically connected by means of the auxiliary conductors magnetic fields of substantially like magnetic potential, inducing current in the armature-winding and passing the samethrough the coils thereof by way of the commutator and brushes for startingthe motor, changing the number of poles of the field to which the armature is subjected, and conveying current between coils of'the armature that are subject to unlike poles of the field through the said auxiliary conductors.

6. The herein described method of operat- .ing an alternating-current dynamo-electric :natingcu rr ent field having a certain number of poles for starting the motor, changing the number of poles of the field after'the motor is started, and providing additional conductors w of resistance-Wire for forming conductingi l 1 I i paths between suoosslve commutator-mg merits of said commutator.- v

,ln Witness whereof I hereunto subscribe my name this 24th day of February, A. D. 1900.; v

'DUGALD o, JACKSON.

Witnesses:

' FLORENCE WICKLIN,

MAX W. ZABEL. 

